With this extension it can be checked the combination of colors to see if it is appropriate for visual perception based on the requirements of the WCAG 1 and WCAG 2.

The extension is shown in the sidebar, and its results are for "normal vision", and for "situations of difficulty in the perception of color (protanopia, and deuteranopia tritanopia)". As a matter of fact, the WCAG 2 formula is considered to be more accurate than WCAG 1, so this result will be displayed by default.

Major Features:

1. The code color code can be introduced both in hexadecimal format (in abbreviated way or not, both with and without pad as it), as RGB (may use different dividers between values, such as the comma or two points ). Example:
   • In hex could be: # FC5 or FC5 or FFCC55
   • In RGB could be: 231.28197 or 231:28:197 or RGB (231.28197)
2. The use of extension colorChecker can be combined, for example, with the extension ColorZilla, because this allows you to select directly from the web document (and copied to the clipboard) the color you want to check. If you have installed the extension ColorZilla, pressing Shift + X or Z will be activated, sending respectively the foreground color or background to colorChecker.
3. You can see the sidebar panel selecting de extension from the tools menu or by clicking on the icon that appears in the status bar, and even with the combination of keyboard alt + c.

Requirements: Firefox: 1.5 – 3.1b3pre